"Tonight’s drop in gas prices is certainly welcome news, [but] refineries in Canada continue to charge an unacceptable premium of five to eight cents per litre above world price for wholesale gasoline," the website, run by former member of Parliament Dan McTeague, said Wednesday.

"This is unacceptable and warrants the attention of public policymakers in Canada to set aside the nonsense advanced by the industries' apologists that the price you pay is based on market fundamentals."

Reacting to the recent increases, federal Industry Minister Tony Clement said Thursday that he would summon oil executives, retailers, and refiners to a parliamentary committee in Ottawa to explain their pricing methods to Canadians. He described current pricing as lacking clarity.

"I think Canadians deserve answers from these execs, and we're going to get them," he told reporters at a news conference in Toronto.

Prices vary across country

In Vancouver, gas was forecast to sell at $1.437 a litre Thursday morning. In Ottawa, the price was $1.29 a litre and in Montreal it was $1.405. In Halifax, the price was set at $1.369 a litre.

In Newfoundland and Labrador, the regulator instructed retailers Thursday to cut prices. The Public Utilities Board lowered the maximum allowed price for all grades of gas by 3.4 or 3.5 cents a litre, with the difference due to rounding for taxes in different parts of the province. That put a litre of self-serve unleaded gas on the Avalon Peninsula, where prices are cheapest, at no more than $1.373.

New Brunswick’s Energy and Utilities Board dropped the maximum price for regular gasoline to $1.325 a litre from $1.359 cents in its weekly gas price setting on Thursday. Dealers frequently sell for less, however, depending on transportation costs. In Saint John, a litre was selling for $1.299 and in Fredericton for $1.302.

Prices rose 6.5 cents a litre on Tuesday in much of Ontario, Montreal and Vancouver, then by another 2.5 cents per litre on Wednesday.

Real relief could take months

Thursday's decrease comes a day after gas futures and oil prices tumbled in the U.S., taking the price of oil below $100 US a barrel. In early trading in Asia on Thursday, oil was down 24 cents a barrel to $97.97.

One industry watcher says any lasting relief from wild price swings could take months to trickle down to the pump.

Jason Parent, a senior partner at energy consultancy The Kent Group, says when supply is as tight as it is right now, significant prices shifts from day to day are to be expected.